In the Long Term Evolution (LTE) project of the Universal Mobile Telecommunication System (UMTS) technique, it is necessary for a terminal to report some uplink scheduling information to a base station, such as a buffer status report of the terminal, i.e. the so-called BSR, in order to assist the base station in scheduling the resources more effectively.
In the LTE system, the BSR is used to represent the data amount in the buffer of the terminal which is permitted. According to the specification of the LTE project, the maximum buffer data amount supported by the terminal is 150K. Furthermore, in the LTE system, there are generally three types of BSR: a long BSR, a short BSR, and a shorten BSR. The long BSR may report the buffer status of four logic channel groups.
To transmit the BSR between the base station and the terminal, a BSR table is provided in both the base station and the terminal. In the BSR table, an interval between 0 and 150K is divided into a plurality of small intervals according to the method of the technical document 1 (3GPP RAN2 document, R2-083101, “Buffer Size Levels for BSR in E-UTRA Uplink”), with the index number of each small interval corresponding to a range of the size of the data amount in the buffer. The content of the technical document 1 is incorporated herein by reference in its entirety. Therefore, the terminal and the base station may report and receive the range of the size of the data amount in the buffer (i.e. the BSR) by transmitting the index number.
Specifically, the terminal finds out the index number in the BSR table according to the size of the data amount in the buffer thereof and reports this index number to the base station, and then the base station obtains the range of the size of the data amount in the buffer (i.e. the BSR) from the BSR table according to the index number.
In the LTE project, codes of 6 bites are defined for reporting the above index number. In this case, the interval between 0 and 150K may therefore be divided into 64 small intervals according to the method of the technical document 1. The corresponding relation between the index numbers of respective small intervals and the ranges of the sizes of the data amounts in the corresponding buffers is stored to form the BSR table.
FIG. 10 shows an example of a BSR table in the existing LTE system. It can be seen that, this BSR table indicates only that the present data amount is over 150K but may not give a more specific numerical value or a numerical value range, when the maximum buffer data amount in the buffer is over 150K.
With the freezing of the LTE project, the study on the fourth generation mobile communication system (LTE-Advanced, LTE-A) technique has been initiated presently. In the LTE-A, requirement for higher data speed is put forward, for example downlink 1 Gbps, and uplink 500 MGbps.
With the development of the LTE-A technique and the further increasing in the data speed, the reportable maximum buffer data amount supported by the terminal will be far beyond 150K, for example go up to 1200K or 1500K. Thus, the BSR table in the existing LTE technique is not able to support any more the maximum buffer data amount reportable by the terminal, so that it is necessary to improve the BSR table for adapting to the new maximum buffer data amount.
One solution is to extend the size of the BSR table. For example, codes of 7 bites are adapted to indicate the index number, and in this case, the number of the interval in the BSR table may reach up to 128.
Another solution is to extend the maximum buffer data amount in the BSR table. For example, in the technical solution provided by the technical document 2 (3GPP RAN2 document, R2-102987, “REL-10 BSR format and buffer size field”), the maximum buffer data amount in the existing BSR table is extended directly to 1200K or 1500K, and then the range between 0 and 1200K or between 0 and 1500K is divided into a plurality of small intervals according to the technical document 1. FIG. 11 shows a BSR table according to the technical solution of the technical document 2, and the maximum buffer data amount is 1200K in the BSR table shown in FIG. 11. Furthermore, in the technical solution of the technical document 2, the existing BSR table is replaced by the extended BSR table.